Fireplace heat exchanger



FIG. 1 is a perspective view of a fireplace heat exchanger showing ournew design;

FIG. 2 is a plan view thereof;

FIG. 3 is a side elevational view thereof, the side of the heatexchanger now shown herein is a mirror image thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a bottom view thereof.

The ornamental design for a fireplace heat exchanger, as shown anddescribed.